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General radical difluoromethylation using difluoroacetic anhydride via photoredox catalysis

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Science China Chemistry 2024年第8期67卷 2637-2646页

作者： Meng He yankai Yang Heng Zhang Zhipeng Guan Zhi-Bing Dong Hong Yi Aiwen Lei School of Chemistry and Environmental Engineering Wuhan Institute of TechnologyWuhan 430205China College of Chemistry and Molecular Sciences and Institute for Advanced Studies(IAS) Wuhan UniversityWuhan 430072China

CF_(2)H-containing molecules play pivotal roles in diverse fields from medicinal chemistry to materials science. However, the application of existing CF_(2)H reagents as a source of CF_(2)H radical is limited by their reactivity and preparation. Herein, we develop a simple and general visible-light-catalyzed radical difluoromethylation reaction of alkenes, dienes, and heteroaromatics using commercially available, easy-to-handle, and low-cost difluoroacetic anhydride as the CF_(2)H reagent. This scalable protocol enables the convenient synthesis of a range of CF_(2)H-containing compounds under mild conditions, exhibiting a broad substrate scope and functional group tolerance. Potential applications are further demonstrated by gram-scale synthesis, sunlight experiments, derivatization experiments as well as the synthesis of bioactive molecules.

关键词： radical difluoromethylation alkenes/dienes/heteroaromatics difluoroacetic anhydride photoredox

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Synergistically enhanced dielectric, insulating and thermally conductive performances of sandwich PMMA based dielectric films

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Progress in Natural Science:Materials International 2024年第3期34卷 591-597页

作者： Dongmei Zhang Yufan Li Yuchao Li Zhonggui Sun Hanxue Zhu Lujia Yang Yanhu Zhan yankai Li Shi Wang Jun-Wei Zha School of Mathematical Sciences Liaocheng University School of Materials Science and Engineering Liaocheng University State Key Laboratory of Organic Electronics and Information Displays & Institute of Advanced Materials (IAM) Nanjing University of Posts & Telecommunications School of Chemistry and Biological Engineering University of Science and Technology Beijing

A tri-layered(B-G-B) dielectric films were simply prepared by alternatively spin-coating boron nitride/polymethylmethacrylate(BN/PMMA, B) and graphene nanosheets(GNS/PMMA, G) compound solutions. The structure, morphology, thermal conductivity, and particularly the dielectric and relaxation behaviors were systematically studied. Results showed that a good exfoliation and dispersion of BN and GNS can be simply achieved through intensive mechanical compounding with PMMA in the internal mixer. The dielectric constant and breakdown strength of the obtained 1-3-1(B-G-B) sandwich composite film reached 4.3(@1 kHz) and 458.6kV/mm, being 119 % and 113 % higher than that of pure PMMA, respectively. Furthermore, the overall thermal conductivity of sandwich 1-3-1 composite increased by 112 % due to the addition of thermally conductive BN and GNS. The sandwich design strategy provided an effective way of achieving good permittivity, high insulation, and improved thermal conductivity simultaneously, showing potential applications in the miniaturization and integration of electronic devices.

关键词： Breakdown strength Composites Dielectric constant Sandwich structure Thermal conductivity

Crosstalk between glioblastoma and tumor microenvironment drives proneural–mesenchymal transition through ligand-receptor interactions

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Genes & Diseases 2024年第2期11卷 874-889页

作者： Yancheng Lai Xiaole Lu yankai Liao Pei Ouyang Hai Wang Xian Zhang Guanglong Huang Songtao Qi Yaomin Li Department of Neurosurgery Institute of Brain DiseaseNanfang HospitalSouthern Medical UniversityGuangzhouGuangdong 510515China Laboratory for Precision Neurosurgery Nanfang HospitalSouthern Medical UniversityGuangzhouGuangdong 510515China

Glioblastoma(GBM)is the most common intrinsic and aggressive primary brain tumor in adults,with a median survival of approximately 15 *** heterogeneity is considered responsible for the treatment resistance and unfavorable ***-mesenchymal transition(PMT)represents GBM malignant progression and recurrence,which might be a breakthrough to understand GBM heterogeneity and overcome treatment *** is a complicated process influenced by crosstalk between GBM and tumor microenvironment,depending on intricate ligand-receptor *** this review,we summarize the autocrine and paracrine pathways in the GBM microenvironment and related ligand-receptor interactions inducing *** also discuss the current therapies targeting the PMT-related autocrine and paracrine ***,this review offers a comprehensive understanding of the failure of GBM-targeted therapy and ideas for future tendencies of GBM treatment.

关键词： Autocrine Glioblastoma Ligand-receptor interaction Microenvironment Paracrine Proneural-mesenchymal transition

Heteroatom Structural Engineering Enables Ethenylene-Bridged Bisisoindigo-Based Copolymers to Exhibit Unique n-Type Transistor Performance

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CCS Chemistry 2024年第2期6卷 473-486页

作者： Yuchai Pan Weifeng Zhang yankai Zhou Xuyang Wei Hao Luo Jinbei Wei Liping Wang Gui Yu Beijing National Laboratory for Molecular Sciences CAS Research/Education Center for Excellence in Molecular SciencesInstitute of ChemistryChinese Academy of SciencesBeijing 100190 School of Chemical Sciences University of Chinese Academy of SciencesBeijing 100049 School of Material Science and Engineering University of Science and Technology BeijingBeijing 100083

Herein,we report three novel electron-deficient aromatics,ethenylene-bridged bisisoindigos 3,3′-((3E,3′E)-((E)-ethene-1,2-diyl)bis(1-(4-decyltetradecyl)-2-oxoind-oline-6-yl-3-ylidene))bis(1-(4-decyltetradecyl)-1,3-dihydro-2H-pyrrolo[2,3-b]pyridin-2-one)(NCCN),3,3′-((3E,3′E)-((E)-ethene-1,2-diyl)bis(1-(4-decyltetradecyl)-7-fluoro-2-oxoindoline-6-yl-3-ylidene))bis(1-(4-decyltetradecyl)-1,3-dihydro-2H-pyrrolo[2,3-b]pyridin-2-one)(NFFN),and(3E,3″E)-6,6″-((E)-ethene-1,2-diyl)bis(1,1′-bis(4-decyltetradecyl)-[3,3′-bipyrrolo[2,3-b]pyridinylidene]-2,2′(1H,1′H)-dione)(NNNN),and their derived donor–acceptor(D–A)copolymers,namely poly[3,3′-((3E,3′E)-((E)-ethene-1,2-diyl)bis(1-(4-decyltetradecyl)-2-oxoindoline-6-yl-3-ylidene))bis(1-(4-decyltetradecyl)-1,3-dihydro-2H-pyrrolo[2,3-b]pyridin-2-one-6-yl)]-alt-[5,6-difluoro-4,7-di[(thiophen-2-yl)-5-yl)]benzo[c][1,2,5]thiadiazole](PNCCN-FBT),poly[3,3′-((3E,3′E)-((E)-ethene-1,2-diyl)bis(1-(4-decyltetradecyl)-7-fluoro-2-oxoindoline-6-yl-3-ylidene))bis(1-(4-decyltetradecyl)-1,3-dihydro-2H-pyrrolo[2,3-b]pyridin-2-one-6-yl)]-alt-[5,6-difluoro-4,7-di[(thiophen-2-yl)-5-yl)]benzo[c][1,2,5]thiadiazole](PNFFNFBT),and poly[(3E,3″E)-6′,6‴-((E)-ethene-1,2-diyl)bis(1,1′-bis(4-decyltetradecyl)-[3,3′-bipyrrolo[2,3-b]pyridinylidene]-2,2′(1H,1′H)-dione-6-yl)]-alt-[5,6-difluoro-4,7-di[(thiophen-2-yl)-5-yl)]benzo[c][1,2,5]thiadiazole](PNNNN-FBT),in which 5,6-difluoro-4,7-di(thiophen-2-yl)benzo[c][1,2,5]thiadiazole(FBT)acts as the electron-donating *** ethenylene-bridging unit reduces the steric hindrance of the three *** of heteroatoms,such as fluorine and sp2-nitrogen atoms,endows them with multiple CH···F,CH···N,and N···S intramolecular hydrogen bonds/nonbinding interactions,resulting in increasing backbone planarity from NCCN,NFFN,to NNNN,and thus from PNCCN-FBT,PNFFN-FBT,to *** found that all copolymers formed an improved molecular packing in the 1-chloronaphthalene(CN)-processed thin film compared with the 1,2-d

关键词： D-A copolymers bisisoindigos heteroatom structural engineering n-type field-effect transistors electron mobilities

Residential energy transition and chronic respiratory diseases

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The Innovation 2024年第3期5卷 33-43页

作者： Hongcheng Wei Qiurun Yu Danrong Chen Mingzhi Zhang Quanquan Guan Bo Hang Antoine M.Snijders Adrian Covaci yankai Xia State Key Laboratory of Reproductive Medicine and Offspring Health Center for Global HealthSchool of Public HealthNanjing Medical UniversityNanjing 211166China Key Laboratory of Modern Toxicology of Ministry of Education School of Public HealthNanjing Medical UniversityNanjing 211166China The Affiliated Wuxi People’s Hospital of Nanjing Medical University Wuxi People’s HospitalWuxi Medical CenterNanjing Medical UniversityWuxi 214023China Biological Systems and Engineering Division Lawrence Berkeley National LaboratoryBerkeleyCA 94720USA Toxicological Centre University of Antwerp2610 WilrijkBelgium

Obtaining clean energy is of prime importance for planetary health and sustainable *** aimed to assess the association between residential energy transition and the risk of chronic respiratory *** data from the Global Health Observatory and Global Burden of Diseases,Injuries,and Risk Factors Study,we delineated the spatial distribution and temporal trends of the population using clean fuels for cooking at a global *** the China Health and Retirement Longitudinal Study,we performed rigorous and well-structured multistage analyses incorporating both cross-sectional and prospective data analyses to examine the associations between solid fuel use,residential energy transition,duration of solid fuel use,and the risk of chronic respiratory *** great progress,huge disparities in access to clean energy persist *** energy transition was associated with a lower risk of chronic respiratory *** the period of 2011–2013,compared with persistent solid fuel users,both participants who switched from solid to clean fuels(adjusted risk ratio[RR]0.78,95%confidence interval[CI]0.62–0.98)and persistent clean fuel users(adjusted RR 0.71,95%CI 0.57–0.89)had significantly lower risk of chronic respiratory diseases(p<0.001 for trend).Consistent associations were observed in the period of 2011–2015 and 2011–*** energy transition from solid to clean fuels could reduce the risk of chronic respiratory *** is a valuable lesson for policy-makers and the general public to accelerate energy switching to alleviate the burden of chronic respiratory diseases and achieve health benefits,particularly in low-and middle-income countries.

关键词： cooking income globally

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“去方程化”的分数应用题教学探究

教学与管理 2024年第5期 32-36页

作者：牛延凯山东省淄博市高新区教育和体育事业中心

分数应用题是小学数学的难点,现有教材中大量借助方程处理分数中的复杂数量关系。《义务教育数学课程标准(2022年版)》将方程内容从小学移出后,亟需形成“去方程化”的分数应用题教学变革。分析现有教材的变迁、对比国外教材,可以发现... 详细信息

分数应用题是小学数学的难点,现有教材中大量借助方程处理分数中的复杂数量关系。《义务教育数学课程标准(2022年版)》将方程内容从小学移出后,亟需形成“去方程化”的分数应用题教学变革。分析现有教材的变迁、对比国外教材,可以发现方程并不是分数应用题教学的必要条件。在不借助方程时,首先通过“量”和“率”的分类讨论,把握分数应用题和整数应用题的迁移联系;进一步通过构建数量关系结构,明晰分数问题中加减乘除列式的算术意义;最后通过比、分数、除法之间的大单元联系,实现分数应用题的整体教学。

关键词：小学数学分数应用题方程 “去方程化”

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基于频域特征的航空轴承智能诊断

航空动力学报 2024年第6期39卷 248-258页

作者：李宏宇苏越陈康王俨剀西北工业大学动力与能源学院西安710072

针对航空发动机滚动轴承的故障诊断,提出一种基于频域特征的故障诊断模型。将原始振动信号进行包络解调预处理,仅取每段数据处理后的512个点作为故障特征,将其作为双向循环长短期记忆网络(BiLSTM)模型的输入,可对内圈故障、外圈故障、... 详细信息

针对航空发动机滚动轴承的故障诊断,提出一种基于频域特征的故障诊断模型。将原始振动信号进行包络解调预处理,仅取每段数据处理后的512个点作为故障特征,将其作为双向循环长短期记忆网络(BiLSTM)模型的输入,可对内圈故障、外圈故障、滚动体故障及每种故障所对应3种不同的故障程度进行诊断。该模型不仅弥补完全由原始振动信号输入导致输入数据冗长,特征不明显等缺点,也弥补由人工提取振动特征来进行故障诊断的不确定性。在滚动轴承公开数据集上进行实验,结果表明故障识别的准确度达到99.8%以上。搭建航空轴承实验器来对方法与模型进行检验。基于频域特征的双向循环长短期记忆网络模型能够更准确地对轴承进行故障诊断,所提方法对于航空发动机滚动轴承故障诊断具有重要工程价值。

关键词：故障诊断特征提取神经网络滚动轴承双向循环长短期记忆网络

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风管机恒风量控制方法研究

家电科技 2022年第S1期 623-627页

作者：彭延凯周洋范雪峰陈林青岛海信日立空调系统有限公司山东青岛266510

根据风机-风道特性曲线,分析了风机系统随风道阻力变化的规律,并基于实验数据分析了恒转速和恒风量下,风量、功率和转速等参数之间的关系,提出了一种基于风机功率检测的恒风量控制方法,通过该恒风量控制方法识别的静压误差在4%以内,风... 详细信息

根据风机-风道特性曲线,分析了风机系统随风道阻力变化的规律,并基于实验数据分析了恒转速和恒风量下,风量、功率和转速等参数之间的关系,提出了一种基于风机功率检测的恒风量控制方法,通过该恒风量控制方法识别的静压误差在4%以内,风量误差在6%以内。

关键词：风管机静压恒风量功率

中国OFDI对“一带一路”沿线国家经济增长的影响路径分析

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国际经贸探索 2024年第6期40卷 85-101页

作者：杨璐璐盖延凯中国矿业大学(北京)共同富裕研究院中国矿业大学(北京)文法学院

自“一带一路”倡议提出以来,中国与沿线国家在多个领域展开了广泛合作并不断加大对沿线国家的直接投资力度,带动了沿线国家的经济增长。文章基于2003~2021年中国对60个“一带一路”沿线国家对外直接投资(OFDI)的面板数据,构建多重链式... 详细信息

自“一带一路”倡议提出以来,中国与沿线国家在多个领域展开了广泛合作并不断加大对沿线国家的直接投资力度,带动了沿线国家的经济增长。文章基于2003~2021年中国对60个“一带一路”沿线国家对外直接投资(OFDI)的面板数据,构建多重链式中介效应模型,实证检验中国OFDI对“一带一路”沿线国家经济增长的影响路径。结果表明,中国OFDI通过基础设施建设、生产投入增加和出口规模增长均能显著促进“一带一路”沿线国家的经济增长,其中,出口规模增长的中介效应最强。链式路径机制分析发现,“一带一路”沿线国家主要通过“中国OFDI→基础设施建设→出口规模增长→经济增长”这一路径实现经济增长。异质性分析发现,除上述路径之外,相对发达国家还可以通过“中国OFDI→生产投入增加→出口规模增长→经济增长”这一路径实现经济增长。

关键词：技术进步产业升级出口增长多重链式中介效应模型经济增长